Hi.(adsbygoogle = window.adsbygoogle || []).push({});

Assume we have a large number of identical boxes of some finite length ##l## and with infinite potential walls. Let's prepare them all in the same momentum eigenstate. Since for eigenstates ##\Delta p=0##, by the uncertainty principle ##\Delta x## should go to infinity. However, since the particles can't leave the boxes, ##l## is an upper limit for ##\Delta x##. How is this possible?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Uncertainty principle if position is restricted

Tags:

**Physics Forums | Science Articles, Homework Help, Discussion**